which were presented by its many harbors and its advantageous location with respect to the great sea routes. Under the Norman kings the commerce of the southern kingdom was passive, rather than active, that is to say, it was carried on, not mainly by its own cities, such as Bari and Amalfi, which had enjoyed great prosperity in the Byzantine period and lost their local independence under the Normans, but by commercial powers from without—Pisa, Genoa, and Venice. The relative importance of each of these varied with the vicissitudes of Italian politics, but among them they shared the external trade of the kingdom. We find the Venetians on the eastern coast, the Genoese and Pisans at Salerno and the chief ports of Sicily, where they had special warehouses and often considerable colonies; and the earliest commercial records of Genoa and Pisa, notably the register of the Genoese notary, John the Scribe, enable us to follow their business from merchant to merchant and from port to port. Sicily served not only as a place for the exchange of exports for foreign products, the cloth of northern Italy and France and the spices and fabrics of the East, but also as a stage in the trade with the Orient by the great highway of the Straits of Messina or with Africa and Spain by way of Palermo and the ports of the western and southern coast. From all this the king took his toll. Without foregoing any of their feudal or domanial revenues or extensive monopolies, Roger and his successors tapped this grow-
